Green catalytic conversion of hydrogenated rosin to glycerol esters using subcritical CO2 in water and the associated kinetics

Using subcritical CO2-enriched high temperature compressed water (HTCW) as a catalyst for the reaction of hydrogenated rosin (HR) and glycerol, the effects of CO2 pressure, temperature, HR to glycerol molar ratio and reaction time were explored. The conversion of HR reached 95.28% under optimized conditions. Kinetic experiments were performed from 230 to 260 degrees C at CO2 pressures between 4.0 and 0 MPa and samples were analyzed using gel permeation chromatography. A new reaction scheme incorporating mono-, di-, and tri-glycerides in a kinetic model was proposed. The activation energies for the esterification ranged from 44.42 to 54.92 kJ mol(-1) when using the CO2-enriched HTCW catalyst, and from 49.66 to 63.67 kJ mol(-1) without CO2. Results from the kinetic model were in good agreement with experimental observations. (C) 2017 Elsevier B.V. All rights reserved.